demo D184

Shadow columns: what changed in Vue

Delta, percent change and a move count against the value at page load

shadow: { of, kind: 'delta' }

This grid adds shadow columns showing each value's delta, percent change and move count against its value at page load. It lets a reader see what has moved since they arrived, as real sortable columns beside the live figures.

Building…

Loading a live grid…

This is the Vue 3 version. A createLatticeGrid component takes the configuration through v-bind, and reactive data flows straight into the grid, so it updates the way the rest of your Vue app does.

The configuration

<link rel="stylesheet" href="https://cdn.latticegrid.dev/lattice-grid@1.108.0/lattice-grid.min.css">
<style>
  #grid > div { height: 460px; }
</style>
<div id="grid"></div>

<script type="module">
  import * as Vue from 'https://esm.sh/vue@3/dist/vue.esm-browser.prod.js';
  import { createGrid } from 'https://cdn.latticegrid.dev/lattice-grid@1.108.0/lattice-grid.esm.min.js';
  import createLatticeGrid from 'https://cdn.latticegrid.dev/lattice-grid@1.108.0/modules/vue.esm.min.js';

  const LatticeGrid = createLatticeGrid({ vue: Vue, createGrid });

  Vue.createApp({
    components: { LatticeGrid },
    data() {
      return {
        config: {
          rowKey: 'id',
          highlightOnChange: { duration: 500 },
          columns: [
            { field: 'symbol', title: 'Symbol', layout: { pin: 'start', width: 120 } },
            { field: 'desk', title: 'Desk', filter: { type: 'set' } },
            { field: 'region', title: 'Region', filter: { type: 'set' } },
            { field: 'price', title: 'Price', type: 'number' },
            // A shadow column is declared against another and maintained by the grid.
            { id: 'delta',  title: 'Change',  shadow: { of: 'price', kind: 'delta' }, type: 'number', format: { signed: true } },
            { id: 'pct',    title: 'Change %', shadow: { of: 'price', kind: 'deltaPercent' }, type: 'number', format: { style: 'percent', signed: true } },
            { id: 'moves',  title: 'Moves',   shadow: { of: 'price', kind: 'updates' }, type: 'number' },
            { id: 'streak', title: 'Streak',  shadow: { of: 'price', kind: 'streak' }, type: 'number', format: { signed: true } },
          ],
          rows,  // one symbol per row: symbol, desk, region, price
        },
      };
    },
    mounted() {
      // A shadow column measures against the value each row had at page load, so
      // it needs a live feed to show anything. This nudges a slice of the book on
      // a timer and pushes the changes with rows.apply; every shadow updates from
      // that call.
      const grid = this.$refs.grid.grid();
      this.timer = setInterval(() => {
        const updates = rows.slice(0, 40).map((r) => ({
          id: r.id,
          price: Math.round(r.price * (1 + (Math.random() - 0.5) * 0.02) * 1e4) / 1e4,
        }));
        grid.rows.apply({ update: updates });
      }, 120);
    },
    unmounted() {
      clearInterval(this.timer);
    },
    template: '<lattice-grid ref="grid" v-bind="config" />',
  }).mount('#grid');
</script>